This invention relates to pulse detonation systems, and more particularly, to a pulse detonation engine bypass and cooling flow, with downstream mixing volume.
With the recent development of pulse detonation combustors (PDCs) and engines (PDEs), various efforts have been underway to use PDC/Es in practical applications, such as combustors for aircraft engines and/or as means to generate additional thrust/propulsion in a post-turbine stage. Further, there are efforts to employ PDC/E devices into “hybrid” type engines which use a combination of both conventional gas turbine engine technology and PDC/E technology in an effort to maximize operational efficiency. It is for either of these applications that the following discussion will be directed. It is noted that the following discussion will be directed to “pulse detonation combustors” (i.e. PDCs). However, the use of this term is intended to include pulse detonation engines, and the like.
One problem, which often arises when employing PDCs in a “hybrid” engine configuration, is the presence of losses due to unsteady pressure waves that are generated by the pulse detonation process. These waves can propagate “upstream” into some of the conventional engine components, for example bypass flow. Stated differently, in some applications the pressure waves at the exit of the PDC nozzle are so great that they travel upstream into bypass or normal compressor flow. This often causes flow reversals within these conventional components which can damage these components and/or adversely affect the overall operation of the engine.
An additional problem associated with the use of PDCs is the large amount of heat generated during operation, which can significantly shorten the operational life of the PDC and related components.
It is also necessary to achieve a desired average exit temperature from the PDC while facilitating stable operation within the detonation chamber. In parallel, it is beneficial to minimize the temperature variation at the exit of the PDC so that the downstream components can achieve maximum thermodynamic efficiency with robust life.
Therefore, there exists a need to prevent the shock losses generated by the detonation and a means to provide sufficient cooling for a PDC during operation, and a means to achieve the desired exit temperature and uniform profile, in a hybrid engine configuration.